I just bought a 91' CRX si with a B16A engine swap. everything seems to be ok but the idle. Runs great cold with the idle at just over or at a grand however after you drive, i'll say 10ish min, the idle will be at 500 drop to 0 then come right back up to 500. Any thoughts anyone?

 

IACV or TPS....those are my guesses

 

yea check the iacv mine did the same thing when i did my swap the first time

 

I just had a similar problem.
check your Vac lines.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vtecb18c &raquo;</TD></TR><TR><TD CLASS="quote">IACV or TPS....those are my guesses</TD></TR></TABLE> thanks for the info so far guys! but i'm new to honda so what are the IACV? as far as the vacume lines just make sure they clean? and Beana did you run into anyother problems with your swap? i'm such a newbi at this but thanks a lot guys!

 

100% fitv

 

IACV-intake air control valve
TPS- throttle postition sensor
as far as the vacuum lines are conserned you dont need to worry about how clean they are you make sure they are all hooked up and their are no leaks

 

Here are the possibilities:

1. Air in your Radiator - check your fluid levels and bleed if necessary.
2. The temp sending unit is faulty - and not sending the correct reading to the ECU.
3. The TPS is bad, and not sending the correct reading to the ECU.
4. The IACV is dirty, and not operating at warm engine temps. This valve costs $150 at most part stores - so try cleaning it before replacing.

This issue occurred in my 1985 CRX, and my 89 Si. Replaced the IACV both times in the end.